package main

import (
	"bytes"
	"fmt"
	"io"
	"os"
)

func main() {
	var myWriter = MyWriter{os.Stdout}
	fmt.Fprintln(&myWriter, "hello")
}

type MyWriter struct {
	io.Writer
}

func (w *MyWriter) Write(p []byte) (n int, err error) {
	return w.Writer.Write(bytes.ToUpper(p))
}
